I was just in Kona last week.
If there was an earthquake there, you wouldn't know it. Kona looks just like it did when I visited them for the first time in 2004, except traffic is a bit worse on Queen Ka'ahumanu Highway as they are widening it to four lanes between Kailua-Kona and the airport. If you will be traveling during "peak" hour, give yourself extra time, especially if going to the airport. And I noticed that Kuakini Hwy has been upgraded as well.
Driving around to the Hilo side, my friend and I noticed a couple of "missing" pedestrian overpasses that had stairways to nowhere on each side, but the horizontal part over the highway was missing. I'm guessing those either collapsed in the earthquake, or were so badly damaged they were taken down.
My friend's knees were giving him problems (old on the job injury) and thus we didn't hike to any of the lava flows. However, a few people I met on the dive boat told me that although the Park Service says it was a 1.5 mile hike to see it from the end of the road, it was in reality closer to a 5 mile hike each way. All agreed it wasn't worth the effort. If you really want to see the lava, you may want to do what catherine did and take a helicopter flight, though it's not cheap.
Oh, and you definitely gotta do the manta ray night dive. It's worth the trip to Kona by itself.